Adaptive processing in time-multiplexed signals

ABSTRACT

Systems and methods are provided for broadcasting a signal. A multiplexer combines a first signal from a first signal source and a second signal from a second signal source as a time divisional multiplexed signal and provides a timing signal, distinct from the time division multiplexed signal, that indicates, for a given time, from which of the first and the second signal source a corresponding portion of the time divisional multiplexed signal originated. A signal conditioning component receives each of the time divisional multiplexed signal and the timing signal and alters the time division multiplexed signal in a manner that prepares the signal for broadcast. The signal conditioning component dynamically alters its behavior according to the timing signal. An antenna transmits the time division multiplexed signal.

RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 16/090,018, filed Sep. 28, 2018, which is theNational Phase of the International Application No. PCT/US17/24732,filed Mar. 29, 2017, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/314,643, filed Mar. 29, 2016. The entirety ofthese applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to RF communication systems and isparticularly directed to systems and methods for adaptive processing intime-multiplexed signals.

BACKGROUND

Time division multiplexing (TDM) is a method of transmitting andreceiving independent signals over a common signal path by means ofsynchronized switches at each end of the transmission line so that eachsignal appears on the line only a fraction of time in an alternatingpattern. The time domain is divided into several recurrent time slots offixed length, one for each subchannel. A sample byte or data block offirst subchannel is transmitted during a first time slot, a secondsubchannel is transmitted during a second time slot, and so forth.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a broadcastingsystem is provided. A multiplexer combines a first signal from a firstsignal source and a second signal from a second signal source as a timedivisional multiplexed signal and provides a timing signal, distinctfrom the time division multiplexed signal, that indicates, for a giventime, from which of the first and the second signal source acorresponding portion of the time divisional multiplexed signaloriginated. A signal conditioning component receives each of the timedivisional multiplexed signal and the timing signal and alters the timedivision multiplexed signal in a manner that prepares the signal forbroadcast. The signal conditioning component dynamically alters itsbehavior according to the timing signal. An antenna transmits the timedivision multiplexed signal.

In accordance with another aspect of the present invention, a method isprovided for broadcasting a signal. A first signal, from a first signalsource, and a second signal, from a second signal source, are combinedas a time divisional multiplexed signal at a multiplexer. The timedivision multiplexed signal is sampled at a digital predistortionadaptation engine. A timing signal, distinct from the time divisionmultiplexed signal, is provided to the digital predistortion adaptationengine that indicates, for a given time, from which of the first and thesecond signal source a corresponding portion of the time divisionalmultiplexed signal originated.

At the digital predistortion adaptation engine, a first set of filtercoefficients is determined from the samples taken at times when thetiming signal indicates that the corresponding portion of the timedivision multiplexed signal originated with the first signal source. Asecond set of filter coefficients are determined from the samples takenat times when the timing signal indicates that the corresponding portionof the time division multiplexed signal originated with the secondsignal source. The second set of filter coefficients is different thanthe first set of filter coefficients. Digital predistortion is appliedto the time division multiplexed signal, such that the first set offilter coefficients is applied to the time division multiplexed signalat times when the timing signal indicates that the corresponding portionof the time division multiplexed signal originated with the first signalsource and the second set of filter coefficients is applied to the timedivision multiplexed signal at times when the timing signal indicatesthat the corresponding portion of the time division multiplexed signaloriginated with the second signal source. The time division multiplexedsignal is transmitted at an associated transmitter.

In accordance with yet another aspect of the present invention, a firstsignal, from a first signal source, and a second signal, from a secondsignal source, are combined as a time divisional multiplexed signal at amultiplexer. A timing signal, distinct from the time divisionmultiplexed signal, is provided to the transmitter automatic levelcontrol that indicates, for a given time, from which of the first andthe second signal source a corresponding portion of the time divisionalmultiplexed signal originated. A first signal parameter for the timedivision multiplexed signal is maintained while the timing signalindicates that the corresponding portion of the time divisionmultiplexed signal originated with the first source. A second signalparameter for the time division multiplexed signal is maintained whilethe timing signal indicates that the corresponding portion of the timedivision multiplexed signal originated with the second source. Thesecond signal parameter is from the first signal parameter. The timedivision multiplexed signal is broadcast at an associated antenna.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a system for generating a time division multiplexedsignal in accordance with an aspect of the present invention;

FIG. 2 illustrates one example of a system for generating a timedivision multiplexed signal in accordance with an aspect of the presentinvention;

FIG. 3 illustrates one example of a method for broadcasting a signal;

FIG. 4 illustrates another example of a method for broadcasting asignal; and

FIG. 5 is a schematic block diagram illustrating an exemplary system ofhardware components capable of implementing examples of the systems andmethods

DETAILED DESCRIPTION

FIG. 1 illustrates a system 10 for generating a time divisionmultiplexed signal in accordance with an aspect of the presentinvention. The system 10 includes a first signal source 12 and a secondsignal source 14 provided to a multiplexer assembly 16. Depending on theimplementation, the first and second signal sources 12 and 14 canrepresent any signal sources that produce signals having significantlydifferent signal characteristics, such as different modulation errorratios, average output power levels, signal-to-noise ratios, andpeak-to-average power ratio (PAPR). Accordingly, the first and secondsignal sources 12 and 14 can represent separate assemblies, independentmodulators operating within a common assembly, or a samesignal-generating subsystem operating in two distinct modes, such as asingle modulating unit dynamically switching between two distinctmodulation schemes. The multiplexer assembly 16 combines the data fromthe first signal source 12 and the second signal source 14 into a timedivision multiplexed signal. It will be appreciated that, in accordancewith an aspect of the invention, the first signal source 12 and thesecond signal source 14 provide signals.

The multiplexed signal is provided to a signal conditioning element 18.The signal conditioning element 18 is a hardware element, for example,implemented as a field programmable gate array, an integrated circuit,or a general purpose processor operatively connected to a non-transitorycomputer readable medium storing software instructions, that alters thetime division multiplexed signal in a manner that prepares the signalfor broadcast at an associated antenna 20. It will be appreciated thatthe signal conditioning element can be part of the exciter or thetransmitter, depending on the desired function of the system and canrepresent multiple components of the system 10 controlled via a timingsignal as described below. Examples of signal conditioning elements 18can include a power amplifier or an automatic level control associatedwith the amplifier, an update engine for an adaptive digitalpredistortion system that predistorts a signal to account for signaldistortion at a power amplifier or other downstream component or anadaptive power control system.

In accordance with an aspect of the present invention, the multiplexerassembly 16 also provides a timing signal to the signal conditioningcomponent 18, such that the signal conditioning component candynamically alter its behavior according to the source associated withthe time-multiplexed signal. It will be appreciated that the timingsignal is distinct from the time division multiplexed signal, such thatit is not extracted from the signal itself, but is provided separately.In one example where the function of the signal conditioning elementdepends on feedback, samples taken during periods when the signaloriginated with the first source 12 can be stored and analyzedseparately from samples taken when the signal originated with the secondsource 14. Similarly, where the signal conditioning component 18 is apower control system, the system could use separate parameters for eachsignal source, such as average power level, peak-to-average ratio, andsignal quality. Where the signal conditioning component is a digitalpredistortion system, the system could generate and apply differentfilter coefficients for each signal source from samples taken during thetime slot associated with each signal. Where the signal conditioningcomponent 18 is a power amplifier or an automatic level controlassociated with the amplifier, the amplifier could be muted for onesignal source to conserve power when that portion of the signal is notrequired.

In one implementation, the first data source 12 provides video formattedaccording to a broadcasting standard utilizing future extension frames,such as the Digital Video Broadcasting, Second Generation Terrestrial(DVB-T2) standard. This standard includes future extension frames,during which the DVB-T2 formatted video data is not transmitted, suchthat the signal is mute or transmitting data from a second source duringthis time. In one implementation, the second data source 14 can providedata modulated according to the Long Term Evolution (LTE) standard andformatted for reception for a mobile device. It will be appreciated thatthe second data source 14 can be an intermediary source of the data, forexample, as one cell within in a network of towers broadcasting mobilesignals.

FIG. 2 illustrates one example of a system 50 for generating a timedivision multiplexed signal in accordance with an aspect of the presentinvention. Data from a first data source 52 is provided to a firstmodulation component 54 configured to modulate the data onto a carrierfor transmission. In the illustrated implementation, the data ismodulated according to the DVB-T2 standard. The modulated signal canthen be provided to a first signal processing component 56, configuredto prepare the signal for transmission, including providingpredistortion to the signal to account for distortion induced within thetransmission path. The first signal processing component 56 can alsoprovide noise reduction to the signal as well as upconverting the signalto a first radio frequency (RF) signal at an appropriate frequency fortransmission.

A second data source 62 provides a second stream of data fortransmission via FEF slots. In the illustrated implementation, thesecond data source 62 carries data formatted for reception for a mobiledevice associated with a first mobile network. It will be appreciatedthat the second data source 62 can be an intermediary source of thedata, for example, as one cell within in a network of towersbroadcasting mobile signals. Data from the second data source 62 isprovided to a second modulation component 64 configured to modulate thedata onto a carrier for transmission. In the illustrated implementation,the carrier is an intermediate frequency signal, and the data ismodulated according to the Long Term Evolution (LTE) standard. Themodulated signal can then be provided to a second signal processingcomponent 66, configured to prepare the signal for transmission,including providing predistortion to the signal to account fordistortion induced within the transmission path. The second signalprocessing component 66 can also provide noise reduction to the signalas well as upconverting the signal to a second RF signal at anappropriate frequency for transmission.

A multiplexer 70 combines the first RF signal and a second RF signalinto a time division multiplexed signal. In this arrangement, the firstRF signal occupies a first set of a plurality of time slots comprisingthe time multiplexed signal, and the second RF signal occupies a secondset of the plurality of time slots. In one implementation, the secondsignal is inserted into a future extension frame associated with thefirst signal, such that the second set of time slots are completelywithin future extension frames for a broadcast standard associated withthe first RF signal. The time-multiplexed signal is then provided to adigital-to-analog converter (DAC) 72 that transforms thetime-multiplexed signal into an analog signal for broadcast at by anassociated transmitter 74 at an antenna 76.

In accordance with an aspect of the present invention, a digitalpredistortion update engine 80 of the system is adapted to provideseparate digital feedback parameters for the two signals. The digitalpredistortion update engine 80 samples the signal just beforetransmission to provide a feedback signal. An analog-to-digitalconverter (ADC) 82 converts the feedback signal into a digital signal.The resulting digital signal is provided to a sample distributioncomponent 84 that demultiplexes the digital signal to split the feedbacksignal into a first stream of samples, representing portions of the timedivision multiplexed signal that originated from the first video source52, and a second stream of samples, representing portions of the timedivision multiplexed signal that originated from the second video source62. To facilitate demultiplexing of the feedback signal, a timing signalcan be provided from the multiplexer 70 to the sample distributioncomponent 86, such that, with a known delay for the feedback path, thesample distribution component 86 can distinguish between the two datasources 52 and 62 from a time at which each sample is received.

The first stream of input samples is provided to a first digitalpredistortion update component 88 and the second stream of input samplesis provided to a second digital predistortion update component 89. Eachof the predistortion update components 88 and 89 is configured toanalyze its respective stream of samples to determine appropriatepredistortion parameters for the signal. For example, a digital signalcorresponding to the sampled signal can be stored locally and comparedto the feedback samples to determine a transfer function of thetransmitter 74 on the signal. An inverse function can then be determinedby each predistortion update component 88 and 89 and provided to itscorresponding signal processing component 56 and 66 for application tothe signal.

In one implementation, the signal processing components 56 and 66 can beimplemented as a common predistortion processing circuit in the signalpath, between the modulators 54 and 64 and the DAC 72. This circuit canbe modified to hold different filtering coefficients for the signalsfrom the two data sources 52 and 62 based on the timing with which theyare multiplexed at the modulator 70. The circuit can receive timinginformation from the timing signal to determine when the signals fromthe different signal sources are active so it can apply the correctcoefficients. In this implementation, a common digital predistortionupdate engine adaption update engine can be used in place of thepredistortion update components 88 and 89 to process the feedbacksamples from the transmitter output, with the engine modified to keep aseparate adaptation result for each data source.

In view of the foregoing structural and functional features describedabove in FIGS. 1 and 2, example methods will be better appreciated withreference to FIGS. 3 and 4. While, for purposes of simplicity ofexplanation, the methods of FIGS. 3 and 4 are shown and described asexecuting serially, it is to be understood and appreciated that thepresent invention is not limited by the illustrated order, as someactions could in other examples occur in different orders and/orconcurrently from that shown and described herein.

FIG. 3 illustrates one example of a method 100 for broadcasting asignal. At 102, a first signal, from a first signal source, and a secondsignal, from a second signal source, are combined as a time divisionalmultiplexed (TDM) signal at a multiplexer. It will be appreciated thatthe first and second signal sources can represent any signal sourcesthat produce signals having significantly different signalcharacteristics, and can include separate assemblies, independentmodulators operating within a common assembly, or a samesignal-generating subsystem operating in two distinct modes, such as asingle modulating unit dynamically switching between two distinctmodulation schemes. At 104, the time division multiplexed signal issampled at a digital predistortion adaptation engine. At 106, a timingsignal, distinct from the time division multiplexed signal, is providedto the digital predistortion (DPD) adaptation engine. The timing signalindicates, for a given time, from which of the first and the secondsignal source a corresponding portion of the time divisional multiplexedsignal originated. Accordingly, the samples from the time divisionmultiplexed signal can be attributed to the appropriate signal source,allowing for separate predistortion of the signal.

At 108, the digital predistortion adaptation engine determines a firstset of filter coefficients from the samples taken at times when thetiming signal indicates that the corresponding portion of the timedivision multiplexed signal originated with the first signal source. Forexample, the first set of filter coefficients can be determined as tomaintain a first modulation error ratio. At 110, the digitalpredistortion adaptation engine determines a second set of filtercoefficients from the samples taken at times when the timing signalindicates that the corresponding portion of the time divisionmultiplexed signal originated with the second signal source. The secondset of filter coefficients can be, and generally will be, different thanthe first set of filter coefficients. In one example, the second set offilter coefficients can be determined as to maintain a second modulationerror ratio that is different from the first modulation error ratio.

At 112, digital predistortion is applied to the time divisionmultiplexed signal, such that the first set of filter coefficients isapplied to the time division multiplexed signal at times when the timingsignal indicates that the corresponding portion of the time divisionmultiplexed signal originated with the first signal source and thesecond set of filter coefficients is applied to the time divisionmultiplexed signal at times when the timing signal indicates that thecorresponding portion of the time division multiplexed signal originatedwith the second signal source. In one implementation, the first set offilter coefficients are applied to the first signal and the second setof filter coefficients are applied to the second signal before the firstsignal and the second signal are combined at the multiplexer at 102. Inanother implementation, predistortion is selectively applied to the timedivision multiplexed signal after the first signal and the second signalare combined at the multiplexer. It will be appreciated that theselective application of the predistortion can be guided by the timingsignal. At 114, the time division multiplexed signal is transmitted atan associated transmitter.

FIG. 4 illustrates another example of a method 150 for broadcasting asignal. At 152, a signal from a first signal source and a second signalsource is combined as a time divisional multiplexed signal at amultiplexer. At 154, a timing signal, distinct from the time divisionmultiplexed signal, is provided to the transmitter automatic levelcontrol that indicates, for a given time, from which of the first andthe second signal source a corresponding portion of the time divisionalmultiplexed signal originated.

At 156, a first signal parameter for the time division multiplexedsignal is maintained while the timing signal indicates that thecorresponding portion of the time division multiplexed signal originatedwith the first source. At 158, a second signal parameter for the timedivision multiplexed signal is maintained while the timing signalindicates that the corresponding portion of the time divisionmultiplexed signal originated with the second source. In accordance withan aspect of the present invention, the second signal parameter can bedifferent from the first signal parameter. Examples of signal parameterscan include values for the average power level of the signal, thepeak-to-average ratio of the signal, and the signal-to-noise ratio ofthe signal. In one implementation, the TDM signal is sampled beforetransmission at the transmitter automatic level control, with the timingsignal used to distinguish between samples originating with the firstsignal source and the second signal source. In this implementation, thesamples can be used as feedback to maintain the first and second signalparameters at 156 and 158. At 160, the time division multiplexed signalis broadcast at an associated antenna.

FIG. 5 is a schematic block diagram illustrating an exemplary system 200of hardware components capable of implementing examples of the systemsand methods disclosed in FIGS. 1-4. The system 200 can include varioussystems and subsystems. The system 200 can be a personal computer, alaptop computer, a workstation, a computer system, an appliance, anapplication-specific integrated circuit (ASIC), a server, a server bladecenter, a server farm, etc.

The system 200 can includes a system bus 202, a processing unit 204, asystem memory 206, memory devices 208 and 210, a communication interface212 (e.g., a network interface), a communication link 214, a display 216(e.g., a video screen), and an input device 218 (e.g., a keyboard and/ora mouse). The system bus 202 can be in communication with the processingunit 204 and the system memory 206. The additional memory devices 208and 210, such as a hard disk drive, server, stand-alone database, orother non-volatile memory, can also be in communication with the systembus 202. The system bus 202 interconnects the processing unit 204, thememory devices 206-210, the communication interface 212, the display216, and the input device 218. In some examples, the system bus 202 alsointerconnects an additional port (not shown), such as a universal serialbus (USB) port.

The processing unit 204 can be a computing device and can include anapplication-specific integrated circuit (ASIC). The processing unit 204executes a set of instructions to implement the operations of examplesdisclosed herein. The processing unit can include a processing core.

The additional memory devices 206, 208 and 210 can store data, programs,instructions, database queries in text or compiled form, and any otherinformation that can be needed to operate a computer. The memories 206,208 and 210 can be implemented as computer-readable media (integrated orremovable) such as a memory card, disk drive, compact disk (CD), orserver accessible over a network. In certain examples, the memories 206,208 and 210 can comprise text, images, video, and/or audio, portions ofwhich can be available in formats comprehensible to human beings.Additionally or alternatively, the system 200 can access an externaldata source or query source through the communication interface 212,which can communicate with the system bus 202 and the communication link214.

In operation, the system 200 can be used to implement one or more partsof a broadcast system in accordance with the present invention. Computerexecutable logic for implementing the broadcast system resides on one ormore of the system memory 206, and the memory devices 208, 210 inaccordance with certain examples. The processing unit 204 executes oneor more computer executable instructions originating from the systemmemory 206 and the memory devices 208 and 210. The term “computerreadable medium” as used herein refers to a medium that participates inproviding instructions to the processing unit 204 for execution, andcan, in practice, refer to multiple, operatively connected apparatusesfor storing machine executable instructions.

What have been described above are examples of the present invention. Itis, of course, not possible to describe every conceivable combination ofcomponents or methodologies for purposes of describing the presentinvention, but one of ordinary skill in the art will recognize that manyfurther combinations and permutations of the present invention arepossible. Accordingly, the present invention is intended to embrace allsuch alterations, modifications, and variations that fall within thescope of the appended claims.

We claim: 1-20. (canceled)
 21. A system comprising: a multiplexer thatcombines a first signal from a first signal source and a second signalfrom a second signal source as a time divisional multiplexed signal andprovides a timing signal, distinct from the time division multiplexedsignal, that indicates, for a given time, from which of the first andthe second signal source a corresponding portion of the time divisionalmultiplexed signal originated; a signal conditioning component thatreceives each of the time divisional multiplexed signal and the timingsignal and alters at least one of the first signal or the second signalin a manner that prepares the time divisional multiplexed signal forbroadcast, a behavior of the signal conditioning component beingdynamically altered according to the timing signal, the signalconditioning component sampling the time division multiplexed signal toprovide feedback, with samples taken at times when the timing signalindicates that the corresponding portion of the time divisionmultiplexed signal originated with the first signal source being storedand analyzed separately from samples taken at times when the timingsignal indicates that the corresponding portion of the time divisionmultiplexed signal originated with the second signal source; and anantenna that transmits the time division multiplexed signal.
 22. Thesystem of claim 21, wherein the signal conditioning component includes adigital predistortion adaptation engine, the digital predistortionadaptation engine maintaining a first adaptation result, including afirst set of filter coefficients, from the samples taken at times whenthe timing signal indicates that the corresponding portion of the timedivision multiplexed signal originated with the first signal source anda second adaptation result, including a second set of filtercoefficients, from the samples taken at times when the timing signalindicates that the corresponding portion of the time divisionmultiplexed signal originated with the second signal source, the firstset of filter coefficients being different than the second set of filtercoefficients.
 23. The system of claim 22, further comprising a firstdigital predistortion component that applies predistortion to the firstsignal using the first set of filter coefficients and appliespredistortion to the second signal using the second set of filtercoefficients.
 24. The system of claim 23, wherein the first set offilter coefficients are calculated to maintain a first modulation errorratio for the first signal and the second set of filter coefficients arecalculated to maintain a second modulation error ratio for the secondsignal.
 25. The system of claim 21, wherein the signal conditioningcomponent includes a transmitter automatic level control.
 26. The systemof claim 25, wherein the transmitter automatic level control controls apower amplifier, such that the power amplifier is muted when the timingsignal indicates that the time division multiplexed signal originatedwith the second source.
 27. The system of claim 25, the transmitterautomatic level control controlling at least a component of atransmitter, such that the transmitter maintains a first peak-to-averageratio (PAR) for the time division multiplexed signal when thecorresponding portion of the time division multiplexed signal originatedwith the first source and the transmitter maintains a secondpeak-to-average ratio (PAR) for the time division multiplexed signalwhen the corresponding portion of the time division multiplexed signaloriginated with the second source.
 28. A method comprising: combining afirst signal from a first signal source and a second signal from asecond signal source as a time divisional multiplexed signal at amultiplexer; providing a timing signal, distinct from the time divisionmultiplexed signal, to a signal conditioning component that indicates,for a given time, from which of the first and the second signal sourcesa corresponding portion of the time divisional multiplexed signaloriginated; maintaining a first signal parameter for the time divisionmultiplexed signal while the timing signal indicates that thecorresponding portion of the time division multiplexed signal originatedwith the first source; maintaining a second signal parameter for thetime division multiplexed signal while the timing signal indicates thatthe corresponding portion of the time division multiplexed signaloriginated with the second source, the second signal parameter beingdifferent from the first signal parameter; and broadcasting the timedivision multiplexed signal at an associated antenna.
 29. The method ofclaim 28, further comprising sampling the time division multiplexedsignal at the signal conditioning component, the signal conditioningcomponent determining from which of the first and the second signalsources a corresponding portion of the time divisional multiplexedsignal originated from the timing signal; wherein maintaining the firstsignal parameter comprises determining the first signal parameter fromsamples taken at times when the timing signal indicates that thecorresponding portion of the time division multiplexed signal originatedwith the first signal and maintaining the second signal parametercomprises determining the second signal parameter from samples taken attimes when the timing signal indicates that the corresponding portion ofthe time division multiplexed signal originated with the second signal.30. The method of claim 28, wherein the first signal parameter is afirst average power level and the second signal parameter is a secondaverage power level.
 31. A method comprising: combining a first signalfrom a first signal source and a second signal from a second signalsource as a time divisional multiplexed signal at a multiplexer;sampling the time division multiplexed signal at a digital predistortionadaptation engine; providing a timing signal, distinct from the timedivision multiplexed signal, to the digital predistortion adaptationengine that indicates, for a given time, from which of the first and thesecond signal source a corresponding portion of the time divisionalmultiplexed signal originated; determining, at the digital predistortionadaptation engine, a first set of filter coefficients from the samplestaken at times when the timing signal indicates that the correspondingportion of the time division multiplexed signal originated with thefirst signal source; determining, at the digital predistortionadaptation engine, a second set of filter coefficients from the samplestaken at times when the timing signal indicates that the correspondingportion of the time division multiplexed signal originated with thesecond signal source, the second set of filter coefficients beingdifferent than the first set of filter coefficients; applying digitalpredistortion to at least one of the first signal or the second signal,such that the first set of filter coefficients is applied to the timedivision multiplexed signal at times when the timing signal indicatesthat the corresponding portion of the time division multiplexed signaloriginated with the first signal source and the second set of filtercoefficients is applied to the time division multiplexed signal at timeswhen the timing signal indicates that the corresponding portion of thetime division multiplexed signal originated with the second signalsource; and transmitting the time division multiplexed signal at anassociated transmitter.
 32. The method of claim 31, wherein applyingdigital predistortion to at least one of the first signal or the secondsignal comprises applying the first set of filter coefficients to thefirst signal and applying the second set of filter coefficients to thesecond signal before the first signal and the second signal are combinedat the multiplexer.
 33. The method of claim 31, further comprisingselectively applying predisortion to the time division multiplexedsignal, according to the timing signal, after the first signal and thesecond signal are combined at the multiplexer.
 34. A system comprising:a multiplexer that combines a first signal from a first signal sourceand a second signal from a second signal source as a time divisionalmultiplexed signal and provide a timing signal, distinct from the timedivision multiplexed signal, that indicates, for a given time, fromwhich of the first and the second signal source a corresponding portionof the time divisional multiplexed signal originated; a signalconditioning component that receives each of the time divisionalmultiplexed signal and the timing signal and alters at least one of thefirst signal or the second signal in a manner that prepares the timedivisional multiplexed signal for broadcast, a behavior of the signalconditioning component being dynamically altered according to the timingsignal, the signal conditioning comprising a transmitter automatic levelcontrol controlling at least component of a transmitter, such that thetransmitter maintains a first signal parameter for the time divisionmultiplexed signal while the timing signal indicates that thecorresponding portion of the time division multiplexed signal originatedwith the first source and the transmitter maintains a second signalparameter for the time division multiplexed signal while the timingsignal indicates that the corresponding portion of the time divisionmultiplexed signal originated with the second source, the second signalparameter being different from the first signal parameter; and anantenna that transmits the time division multiplexed signal.
 35. Thesystem of claim 34, wherein the first signal parameter is a firstsignal-to-noise ratio and the second signal parameter is a secondsignal-to-noise ratio.
 36. The system of claim 34, wherein the firstsignal parameter is a first average power level and the second signalparameter is a second average power level.
 37. The system of claim 34,wherein the first signal parameter is a first peak-to-average ratio andthe second signal parameter is a second peak-to-average ratio.
 38. Thesystem of claim 21, wherein the first signal comprises data formattedaccording to a broadcasting standard and the second signal comprisesdata formatted according to a mobile standard.
 39. The method of claim28, wherein the first signal comprises data formatted according to abroadcasting standard and the second signal comprises data formattedaccording to a mobile standard.
 40. The method of claim 31, wherein thefirst signal comprises data formatted according to a broadcastingstandard and the second signal comprises data formatted according to amobile standard.
 41. The system of claim 34, wherein the first signalcomprises data formatted according to a broadcasting standard and thesecond signal comprises data formatted according to a mobile standard.